Sanders Associates Limited

Jacob Schwartz

Victor A Misek

An optical radar is disclosed in which fine vernier range and angular displacement accuracy is achieved by projecting a burst of coherent pulses so as to strobe a target passing through the field of view of the projection apparatus. The use of the pulse burst permits the most recent information to be utilized in obtaining the target track. Prior to projection, the pulses in the burst are sampled. The resulting signal is delayed by an amount corresponding to course range and is directed down one of a pair of oppositely directed delay lines. The signals returned from the target are detected by a sectorized receiver, with an electrical output signal from a detector in one of the sectors being applied to the other delay line in the corresponding pair, such that the signal corresponding to the returned pulse propagates in a direction opposite to that of the sampled signal corresponding to the transmitted pulse. The delay lines are tapped at various points corresponding to vernier range and each pair of taps is coupled to a device which ascertains the coincidence of counter-propagating pulses, thereby to establish the vernier range of the target from the projection apparatus. Angular displacement from boresight is measured as a function of the sector occupied by the target, with the number of pairs of oppositely directed delay lines corresponding to the number of sectors in the receiving apparatus. In one embodiment, a waterfall type display is used which displays angular displacement versus vernier range such that an accurate target track may be obtained. The receiving apparatus may be provided with zoom optics so as to vary the vernier range and angular displacement scales.

Enhanced accuracy optical radar

A sensibe heat storage unit is provided which has a 'step function' thermal gradient, and is constructed so as to have alternated regions of different thermal conductivity along the flow path through the unit such that, in one embodiment, there are spaced elements within the storage unit having transverse conductivities higher than the conductivity of the material in the spaces therebetween. This permits discharge of the storage unit at a uniform temperature until the storage unit is emptied.

Sensible heat storage unit

There is herein disclosed a laser detector and spectral analyzer comprising a plurality of photoelectric detector elements, at least, two of which are suitably masked and disposed behind a wedge type interference filter. An additional detector element is operated without any mask or filter. The detector output signals are electronically processed to provide a substantially instantaneous and independent indication of the mean spectral wavelength, spectral width, total power and pulse length of radiant energy incident upon the apparatus.

Laser detector and spectral analyzer

An improved long-life design for solar energy receivers provides for greatly reduced thermally induced stress and permits the utilization of less expensive heat exchanger materials while maintaining receiver efficiencies in excess of 85% without undue expenditure of energy to circulate the working fluid. In one embodiment, the flow index for the receiver is first set as close as practical to a value such that the Graetz number yields the optimal heat transfer coefficient per unit of pumping energy, in this case, 6. The convective index for the receiver is then set as closely as practical to two times the flow index so as to obtain optimal efficiency per unit mass of material.

Solar energy receiver

A method and apparatus are provided for increasing the heat transfer efficiency of a heat exchanger by utilizing a high intensity RF field. Either an ion stream generated by the RF field or the RF field itself results in the efficiency increase and the rate at which the fluid acquires energy from the heat exchanger is enhanced to the extent that the boundary layer normally present at the walls of the heat exchanger which impedes the transfer of heat from the heat exchanger to the fluid breaks down during this process. The RF technique is utilized in one unique application for increasing the efficiency of solar energy receiver which operate at temperatures exceeding 1,500.degree. F in that the system eliminates arcing which would occur due to the high temperatures involved, if electrostatic (D.C.) ion spray devices were used. Arcing elimination is achieved both by the use of RF energy and by shielding the RF electrode or probe from contact with the heat transfer fluid with a dielectric member through which the RF field penetrates. In one embodiment a broad spectrum high voltage RF signal is generated by a Tesla coil to produce the RF signal. Alternatively, pulsed high RF energy of a single frequency may be used. This energy may be generated by a conventional magnetron and may be transmitted by a wave guide with a reentrant cone at the front of the solar receiver so that both focused solar energy and the RF energy impinge on the heat exchanger from the same direction.

Method and apparatus for increasing heat transfer efficiency

Combined optical and electronic apparatus provide for various types of image enhancement by producing two images of the same scene which differ by a predetermined property, and by electronically subtracting the images to yield a video difference signal which emphasizes or deemphasizes a predetermined characteristic of the scene at which the apparatus is pointed. Various types of image enhancement are obtained by simultaneous scanning of the images produced by two imaging systems in which a relative difference in properties between the images such as deliberate misalignment, optical density difference, image resolution, image magnification or image receptor displacement is introduced to create a particular type of enhancement. The intensities from pairs of scanned spots are subtracted on a point-by-point basis to yield a video difference signal which when displayed provides an image enhanced in a particular manner. Property differences are in general introduced in the aperture plane, at the optics or in the image plane. The subject system can be arranged for edge enhancement, size discrimination, emphasis of lines in a predetermined direction, peripheral image enhancement, and central image or boresite enhancement. This system is particularly useful in clutter rejection for TV-based target tracking systems.

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Arlington, MA, United States of America

Jacob Schwartz